Cigarette packaging machine control and monitoring system

ABSTRACT

A control and monitoring system for cigarette packaging machines comprises a control station (1) connected in cascade to each of a plurality of remote stations (2 and 3) in turn, in a ring. The control station 1 supplies an interrogation signal to a D-type latch (20, 30) of the first remote station, which changes state on the next clock pulse edge and applies an interrogation signal to the D-type latch of the second remote station so that the stations are sequentially interrogated in essentially non-overlapping time periods. An interrogated station communicates with the control center (1) via an information line (16) either to receive machine control signals to be passed on to a machine or machine part with which the remote station is associated, or to send machine fault signals indicating a fault in the associated machine or machine part.

The present invention relates to a cigarette packaging machine controland monitoring system, e.g. for supplying periodic control signals toeach of a plurality of parts of a packaging machine or to each of aplurality of packaging machines, and for monitoring faults or otherspecial conditions in such machines or machine parts.

A cigarette packaging operation comprises a large number of oftendelicate operations which need to be initiated reliably and rapidly inpredetermined and periodically repeated sequences. In addition, themachine parts performing these delicate operations are subject to faultsand it is highly desirable in the cigarette industry for such faults tobe determined and located quickly.

Normally, cigarette packaging machines have control and monitoringsystems which require separate wires running from a central control toeach of the plurality of machines or machine parts. Such systems resultin complex wiring systems which are expensive, difficult to install andmaintain, and tend to be unreliable as wires can break, thus affectingthe operation of the system without being noticed immediately. Thecomplexity of such known systems also renders them not easily adaptableto expansion to control and monitor a larger number of machineoperations.

According to one aspect of the present invention there is provided apackaging machine, for packaging cigarettes or other rod-like articlesof the cigarette industry, comprising: a plurality of separate machineparts for effecting respective operations associated with suchpackaging; a plurality of remote stations respectively connected to someor all of said parts, each station comprising an input station arranged(when interrogated) to receive signals from the respective partsignifying the presence of a fault or other special condition, orcomprising an output station being arranged (when interrogated) tosupply a machine control signal to the associated part; a control centerstation connected with all the remote stations in cascade, and includingmeans for integrogating the first remote station in the cascade, eachstation including means for relaying an interrogation signal to the nextstation so that the remote stations are sequentially interrogated inturn, the system including also an information line for transferringfault and control signals between the remote stations and the controlcenter station.

Preferably the stations are connected in cascade in a ring so thatinterrogation control signals propagate from the control station,through all the remote stations and return to the control station.

Hence, according to a second aspect of the invention there is provided acontrol system comprising: a plurality of stations including a pluralityof remote stations and a control station for interrogating the remotestations; connecting means coupling the stations in cascade in a ring;an information line connected to all the stations for transferringinformation between the control stations and an interrogated remotestation; the control station including means for generating aninterrogation control signal and being arranged to supply theinterrogation signal to the first station in the ring; and each stationincluding means for relaying a received interrogation signal after adelay to the next station in the ring so that the stations arerepeatedly sequentially interrogated during respective essentiallynon-overlapping time periods.

A warning device may be operated, if the interrogation signal does notreturn to the control station within a preset time, to indicate linefaults.

Each remote station preferably includes an indicating device, e.g. anLED for indicating when the associated remote station is beinginterrogated.

Hence the location of a line fault may be identified if the controlstation has means for manually applying an interrogation signal to theremote stations to light up all the LED's between the control stationand the line fault.

The information line is preferably a two-way closed loop line.

The relay means may comprise a bistable device such as a D-type latch.

According to the third aspect of the present invention there is provideda control system comprising a control center station; a plurality ofremote stations; a transmission line network interconnecting the controlcenter station and the remote stations and including a clock line and aninformation line, each common to all the stations, and a control lineconnecting the stations in cascade so that a control signal from thecontrol center sequentially enables the stations during successiveessentially non-overlapping time periods to communicate with theinformation line, each station comprising a first bistable devicearranged to be clocked from the clock line and a second bistable devicearranged to be clocked by the output of the first bistable device forcommunicating with the information line during the respective timeperiod.

The second bistable devices of each input station are preferablyarranged for storing a fault (or other special condition) when it occursso that it can be transmitted to the control station when the associatedremote input station is next interrogated.

Multiplexing means is preferably provided in the control center stationto enable a signal to be routed between input/output stations andoutput/input ports at the control center, each output/input port beinguniquely associated with a station.

For a better understanding of the present invention and to show how thesame may be carried into effect, reference will now be made to theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram of a system according to the presentinvention;

FIG. 2 is a circuit diagram of an input station of the system of FIG. 1;

FIG. 3 is a circuit diagram of an output station of the system of FIG.1;

FIG. 4 is a circuit diagram of the control center of the system of FIG.1;

FIG. 5 is a timing diagram of signals pertaining to the system of FIG.1.

FIG. 1 shows a control center 1 and four remote stations 2 and 3connected together in a ring by wires 4. In practice, more than fourstations will be connected in the ring, as is indicated by the chaindotted line in the wires 4. Each station may be associated with amachine or with a part of a machine to be controlled or monitored and iseither an input station 2 (FIG. 2) for detecting faults in itsassociated machine or machine part, or an output station 3 (FIG. 3) forcontrolling, e.g. switching on or off, its associated machine or machinepart.

The control center 1 controls the stations 2 and 3 by sequentiallyinterrogating them in a time division manner, to be explainedhereinafter, so that the input stations 2 deliver information to thecontrol center 1, and the output stations 3 receive information from thecontrol center 1, each in its own discreet time slot which identifiesthe station which is communicating.

Information received from or to be sent to each station 2 and 3 isdelivered to or from the control center 1 via linking circuitry 5 andinterface lines 6 and 7 respectively. The number of interface lines 6corresponds to the number of stations. Interface lines 6 are linked tothe input stations 2 and receive, for example, fault signals deliveredby the input stations 2 to the control center 1. Line 6 consists of abuffer amplifier 8 with a feedback resistor 9 connected across it tokeep information, once received from the control center 1, at the outputof line 6 even after the information signal is removed from the input toamplifier 8 while the other stations are interrogated. An indicatingdevice such as an LED (not shown) may be connected to the line 6 tolight-up when the information signal indicates that a station hasdeteced a machine fault.

Line 7 has an amplifier 10 for feeding in signals for an output station3.

The wires 4 comprise a clock line 12, an interrogation control line 14,an information line 16 and a reset line 18 together with power lines +and 0. These lines run, as shown, from the control center 1 to eachstation 2 and 3 in turn and back to the control center 1.

FIGS. 2 and 3 show an input and an output station 2 and 3 respectively.Each comprises two positive edge triggered D-type bistables 20, 22 and30, 32 respectively, connected as shown.

The first bistable of each station (20, 30) receives interrogationcontrol signals on control line 14 from the previous station (or fromthe control center 1 in the case of the first station), delays theinterrogation control signal and passes it on to the next station. Lightemitting semi-conductor devices such as LED's 24, 25 are provided at theoutput of each first bistable 20, 30 to indicate when that station isbeing interrogated.

The second bistable of each station (22, 32) acts as a store for theinformation to be transferred to or from the control center 1. After thefirst bistable in a station receives the interrogation control signalvia line 14, then the second bistable 22, 32 communicates suchinformation with the control center 1 via information line 16.

Control center 1 supplies clock pulses ("a" in FIG. 5) on clock line 12to the first bistable of each station 20 (FIG. 2) and 30 (FIG. 3)continuously. At the start of each interrogation cycle, the controlcenter 1 sends a reset pulse on line 18 to reset the first bistables 20(FIG. 2) and 30 (FIG. 3). Sequentially, an interrogation control pulseis generated ("b" FIG. 5) by the control center 1 and received at the"D" input of the first bistable 20 of the first station 2 (FIG. 1) inthe ring at time t₁ (FIG. 5). The first bistable 20 changes state at thenext positive-going clock pulse edge, at time t₂ in FIG. 5, causing its"Q" output to go "high" and pulse "c" in FIG. 5 to be generated andpropagated to the next station 3 (FIG. 1). Simultaneously the "Q" outputof the first bistable 20 goes "low" and this negative-going pulse isapplied as an enable signal to the clock input of the second bistable22. Bistable 22 has its "D" and "R" inputs connected to ground and its"S" input connected to receive a positive voltage if there is a fault inthe machine or machine part associated with that station. This isachieved, in this example, using an opto-coupler device 26 whose outputgoes "high" when a transducer feeding it (not shown) detects a machinefault. Of course the input station could be used to monitor anyspecified condition so long as a suitable transducer for detecting thecondition is available and connected to the opto-coupler 26. Hence, if amachine fault (or other specified condition) is present, then the "S"input of bistable 22 is "high"; therefore bistable 22 is set, i.e. its"Q" output is "high". The output of the first bistable 20 interrogatesbistable 22 to determine its state, i.e. to determine whether a faultexists at the machine associated with that station. It does this viadiodes 31 and 33 which act as an "AND" gate. If the "Q" outputs of bothbistables 20 and 22 are "high", then point 35 is "high" and transistor37 is switched on. This causes a negative pulse, coincident with thepositive pulse at the "Q" output of bistable 20, to appear on theinformation line 16 in a unique time slot t₂ -t₃ ("d" in FIG. 5)identified with the first station. When the "Q" output of bistable 20goes "low" again, the "Q" output goes "high" resetting bistable 22 ifthe fault has disappeared, i.e. if "S" is "low".

The positive at the "Q" output of the first bistable 20 of the firststation 2 ("c" in FIG. 5) is propagated to the next station, e.g. to theoutput station 3 illustrated in FIG. 3. The operation of this outputstation will now be described. This delayed control pulse is received atthe "D" input of the first bistable 30, causing bistable 30 to changestate at the next positive-going clock pulse edge, i.e. at time t₃ inFIG. 5. Hence pulse "e" (FIG. 5) appears at the "Q" output of bistable30 and propagates to the next station. Pulse "e" (FIG. 5) is alsoapplied to the clock input of the second bistable 32 of this outputstation 3. If the control center 1 desires to pass a machine controlsignal to a machine or device associated with this output station 3 thenthe control center 1 will apply the machine control signal to"information" line 16, which is connected to the "D" input of the secondbistable 32, in the appropriate time slot for this station, which is t₃to t₄ (FIG. 5). The clock input to bistable 32 will cause the machinecontrol signal applied to the "D" input to be passed to the "Q" output(not shown) of bistable 32 causing the "Q" output to adopt thecomplementary logic state (i.e. "low" in this example). The machinecontrol signal is then passed to the device to be operated, in thisexample from the "Q" output of bistable 32 via buffer amplifier 27,optocoupler 28 and output transistor 29.

Hence in this example it can be seen that the first station 2 isinterrogated in the period t₂ to t₃ and passes a machine fault signal tothe control center 1 via line 16 during that period, and subsequentlystation 3 is interrogated during period t₃ to t₄ during which time itreceives a machine control signal from the control center 1 via line 16.Subsequent stations are interrogated in the same way in subsequent timeperiods. Race hazards are prevented by connecting capacitors in theinterrogation control line, as shown, so that the interrogation controlpulses are slightly elongated, as shown at (b) and (c) in FIG. 5.

FIG. 4 shows the circuit of the control center 1. There are four outputterminals 12, 14, 16 18 and four input terminals 12A, 14A, 16A, 18Acorresponding to the start and finish respectively of the lines 12, 1416 and 18 of FIGS. 1 to 3.

The control circuit comprises a pulse generator 34 connected to acounter 36 which drives a multiplexer 38. Information such as machinecontrol signals for output stations 3 and fault signals from inputstations 2 are applied from/to the multiplexer 38 via terminals 16, 16A,transistor 40 and information terminal 42. A number of multiplexeroutput ports 44 is provided which corresponds to the number ofinput/output stations in the system. These output ports are connectedvia linking circuit 5 to appropriate interface lines 6 and 7 (FIG. 1).The multiplexer 38 and the counter 36 operate to connect each outputport in turn to information terminal 42 in such a way that signals canpass in either direction.

Other circuit elements are provided for self-checking purposes fordetecting faults in the operation of the control circuit itself.Bistable 45 detects if there is a break in the system ring by monitoringwhether or not the control returns to terminal 14A within apredetermined time period, i.e. before the counter 36 has overloaded.Bistable 46 checks the reset signal returns, via terminal 18A. If eitherthe control signal or the reset signal does not return, a fault signalis generated, after a delay by delay circuit 47, at terminal 48 whichmay light an LED or operate an audible warning device (not shown).

Bistable 50 and "AND" gate 52 provide the interrogation control signalat terminal 14 to be delivered to the stations via line 14. Bistable 54together with gates 56, 57, 58 provides a "RESET" signal via terminal 18at the start of each interrogation cycle.

The operation of the control center 1 will now be explained in moredetail.

When the power (Vcc) to control center 1 is first turned on, capacitor59 at the input to NAND gate 57 is uncharged, so the output of gate 57is "high". Once capacitor 59 is charged, the output of gate 57 goes"low". Hence a pulse signal is generated at the output of gate 57 andforms an internal reset pulse at the output of "OR" gate 56. This resetscounter 36, bistables 54, 45 and causes the output of "AND" gate 58 togo "high" generating a "RESET" signal at output terminal 18 whichpropagates round line 18 resetting the first bistables (e.g. 20, 30) ofall the input/output stations 2,3. The internal reset signal also setsbistables 46 and 50. Bistable 46 is reset almost instantaneously as the"RESET" signal reappears at "RESET IN" terminal 18A. If there is a breakin the reset line 18 and the "RESET" signal does not reappear atterminal 18A then the "high" "Q" output of bistable 46 will cause afault signal to be generated, via "OR" gate 60, delay circuit 47 and"NAND" gate 62, at terminal 48.

The "Q" output of bistable 50 remains "high" until the next clock pulseso that the "Q" output is a negative-going pulse having a length equalto the clock pulse period. This is applied to gate 52 to generate apositive-going control pulse at terminal 14 (signal "b" in FIG. 5).

The interrogation control pulse then propagates sequentially through thestations 2 and 3 along line 14 as explained above with reference toFIGS. 2 and 3. Counter 36 drives multiplexer 38 through its states,exchanging "information" between each of the terminals 44 in turn andline terminal 42 in time periods appropriate to the station beingaddressed.

When the interrogation control pulse has propagated through all thestations it arrives back at the control center at terminal 14A "CONTROLIN" signifying the end of an interrogation cycle. It causes bistable 54to change state at the next positive going clock pulse, applying apositive-going pulse from the "Q" output of bistable 54 to an input of"OR" gate 56, causing an internal reset and a "RESET" pulse to begenerated again, resetting the whole system and starting theinterrogation cycle off again by generating another interrogationcontrol pulse at terminal 14.

If there is a break in the control line 14 then the interrogationcontrol pulse will not return to terminal 14A. The counter 36 will reachits maximum count and generate an "OVERLOAD" signal to deactivatemultiplexer 38 via gate 61 and to clock bistable 45, via AND gate 63, togenerate a fault signal at terminal 48, via elements 60, 47 and 62. The"OVERLOAD" signal also stops counter 36 via gate 65.

To find out where the break in the circuit has occurred an operator willactivate switch 64 which applies a positive-going edge to line 14 viagate 52. This causes the "Q" outputs of all the first bistables of thosestations whose control lines 14 are before the break and are stillconnected to terminal 14 of the control center 1, to go "high", lightingall the LED's before the break. Hence the break point is easilydetermined. It should be noted that a break in the information line isnot as serious as a break in the interrogation control and reset lines.A single break will not stop the transfer of information because theinformation can travel either way round the loop formed by line 16. Adouble break would stop the transfer of information to/from the stationsbetween the breaks.

To ensure that the multiplexer 38 is properly synchronised to theappropriate time periods for each station, the clock pulse is fed backto the control center at terminal 21A and the "CLOCK OUT" and "CLOCK IN"pulse phases are compared in "exclusive OR" gate 67. This is importantas the clock pulses obviously take a finite time to propagate around thering of stations.

Hence it can be seen that a system as described herein is particularlyreliable and has a self-checking mechanism which provides for simplelocation of many station or control center faults. The system is alsovery easy to expand as extra stations can be added into the ring in anyposition without need for fundamental change to the control circuit (solong as the capacity of the multiplexer is not exceeded).

It will be appreciated that alternative equivalent combinations of logicelements to those illustrated and herein described may be used to equaleffect.

A control system as herein described is particularly useful forcigarette packing machines but it may also be used to advantage oncigarette handling or making machines or indeed on machines notconnected with the cigarette industry.

As a specific example, the control system herein described may be usedon the Molins HLP 4 cigarette packaging machine.

In this case input stations will be connected to, for example, acigarette ends detector, a missing cigarette detector, a foil "run out"detector, a missing bundle detector, a broken packet detector, and amissing long flap detector, among others.

Output stations will be connected to control a reject solenoid, a gumflow solenoid, a gum lift solenoid, a main motor brake solenoid, blankreservoir solenoids, and a wrapper link up, amongst others.

Some of the information collected by input stations will be fed to amemory and used to determine the information fed to output stations. Forexample if a missing cigarette detector determined that a cigarette wasmissing, this information would be fed to the appropriate input station.Upon interrogation, that input system would send the missing cigaretteinformation to the control station which would route the information toa memory. The memory would then store the information for an appropriatetime, i.e. until the faulty packet had reached a rejection area. Whenceit would send a signal back to the control center station for passingonto the output station connected to the reject solenoid which wouldthen reject the faulty packet. Obviously extra timing circuits areneeded for controlling the memory in the case of some of the operations.

We claim:
 1. A packaging machine, for packaging cigarettes or otherrod-like articles of the cigarette industry, comprising a plurality ofmachine parts for effecting respective operations associated with suchpackaging, a plurality of remote stations respectively connected to atleast some of said parts, at least one of said remote stationscomprising an input station arranged, when interrogated, only to receivesignals from the respective part signifying the presence of a fault orother special condition, and at least another of said remote stationscomprising an output station arranged, when interrogated, only to supplya machine control signal to the associated part, a control stationconnected with all of the remote stations in cascade and including meansfor interrogating the first remote station in the cascade, each stationincluding means for relaying an interrogation signal to the next stationso that the remote stations are sequentially interrogated in turn, andmeans including an information line connected to said remote stationsand said control station for transferring fault and control signalsbetween the remote stations and the control station.
 2. A packagingmachine according to claim 1 wherein the stations are connected incascade in a ring.
 3. A packaging machine according to claim 1 whereinsaid control station comprises a set of input/output ports andmultiplexing means arranged for connecting respective input/output portto their associated remote stations.
 4. A packaging machine according toclaim 1, wherein the information line is a closed loop to which each ofthe stations is connected such that information signals can betransferred between the control station and an interrogated remotestation in either one of the two opposite directions round the loop. 5.A packaging machine according to claim 2 or 4 wherein the controlstation comprises means for operating a warning device if theinterrogation control signal is not received back at the control stationwithin a preset time, thereby to determine line faults in the system. 6.A packaging machine according to claim 1 wherein each remote stationcomprises an indicating device for indicating when a remote station isbeing interrogated.
 7. A packing machine according to claim 3 whereineach of said input/output ports has a light emitting device forindicating that a signal has been received from or sent to itsassociated remote station.
 8. A packaging machine according to claim 1wherein each input station includes a latching circuit arranged forstoring a fault, or other special condition, signal when it occurs, sothat it can be transmitted to the control station when the remotestation is next interrogated.
 9. A packaging machine according to claim1 wherein said relaying means of each station comprises a bistabledevice having its input connected to the output of the bistable deviceof the previous station, and its output connected to the input of thenext station.
 10. A packaging machine according to claim 9 wherein thecontrol station comprises means for generating a clock pulse train on aclock line which is connected to all the stations to clock the bistabledevices thereof.
 11. A packaging machine according to claim 10comprising means for resetting all of the first bistable devices at theend of an interrogation cycle.
 12. A packaging machine according toclaim 8 wherein the latching circuit is a second bistable device.
 13. Apackaging machine according to claim 12 wherein the relaying meansincludes a first bistable device and the second bistable device isarranged to be clocked in synchronism with the output of the firstbistable device.
 14. A machine for handling or processing material,consisting of a plurality of machine parts for effecting respectiveoperations associated with said handling or processing; a plurality ofremote stations respectively connected to at least some of said parts,said remote stations including at least one input station and at leastone output station; a control station for receiving condition signalsfrom said input station and for supplying control signals to said outputstation; and connection means for connecting said control station andsaid remote stations to operate in cascade to supply signals to orreceive signals from said control station in respective time slots of aperiodically repeated time frame; whereinsaid connection means includesa clock line, an interrogation line and an information line; saidcontrol station includes first means for applying clock signals to saidclock line, second means for periodically applying an interrogationsignal to said interrogation line, and third means for supplying controlsignals to or receiving condition signals from said information line;and said remote stations each include fourth means responsive to saidinterrogation signal and a clock pulse received on said connection meansfor generating an enable signal in the remote station during an assignedtime slot of said periodically repeated time frame, and fifth meansresponsive to said enable signal for applying a condition signal to orreceiving a control signal from said information line in conjunctionwith an associated one of said machine parts.
 15. A machine according toclaim 14, wherein said third means includes multiplexing means forselectively connecting said information line to a plurality ofinput/output terminals so that control signals are supplied to saidinformation line from respective input terminals and condition signalsare supplied to respective output terminals from said information lineduring the time slots of said periodically repeated time frame assignedto said respective input and output terminals.
 16. A machine accordingto claim 14, wherein said clock line is a continuous line which isconnected to said fourth means in each remote station and said fourthmeans includes means connected in series with said interrogation linefor reproducing said interrogation signal in each terminal with apredetermined delay.
 17. A machine according to claim 16, wherein saidconnection means connects said control station and said remote stationsin a loop.
 18. A machine according to claim 17, wherein said controlstation includes means for operating a warning device if saidinterrogation signal applied to said interrogation line is not receivedback at the control station within a preset time.
 19. A machineaccording to claim 14, wherein said fifth means in each remote stationincludes storage means for storing a condition signal received from anassociated machine part or a control signal received from saidinformation line.
 20. A machine according to claim 14, wherein saidremote stations are connected in parallel to said clock line and saidinformation line, while said interrogation line connects said remotestations in cascade so that said interrogation signal is passed alongsaid connection means from one remote station to the next in successivetime slots.
 21. A machine according to claim 14, wherein saidinformation line is a continuous line and said fifth means in eachremote station is connected to said information line in parallel to thefifth means of all other remote stations.
 22. A machine according toclaim 14, wherein said fourth means in each remote station comprises afirst bistable circuit having its input connected to the output of thefirst bistable circuit of the previous station and its output connectedto the input of the first bistable circuit of the next station.
 23. Amachine according to claim 22, wherein said information line is acontinuous line and said fifth means in each remote station comprises asecond bistable circuit connected to said information line in parallelwith the second bistable circuits of said other stations.
 24. A machineaccording to claim 17, wherein said control station includes means forgenerating a warning signal if the interrogation signal applied to saidinterrogation line is not received back at the control station within apreset time.
 25. A packaging machine, for packaging cigarettes or otherrod-like articles of the cigarette industry, comprising:(a) a pluralityof separate machine parts for effecting respective operations associatedwith such packaging; (b) a plurality of remote input stations and aplurality of remote output stations associated with the respectivemachine parts; (c) connecting means linking the stations in cascade in aring and including a clock line, an interrogation line and aninformation line; (d) a control station connected in the ring and havingmeans for interrogating an adjacent remote station in the ring byapplication of an interrogation signal thereto on said connecting means;each remote station having a first bistable device for relaying aninterrogation signal received from a previous station to the nextstation in the ring and latching means for applying data to or receivingdata from the information line in response to said first bistable devicewhen that remote station is interrogated.
 26. A machine for handling orprocessing material, consisting of a plurality of machine parts; aplurality of remote stations respectively connected to some or all ofsaid parts, each station comprising an input station arranged whenenabled to receive a signal from an associated machine part, signifyingthe presence of a fault, or comprising an output station arranged whenenabled to supply a machine control signal to an associated parteffecting a change in the operating procedure of the machine, therebeing a plurality of each of these types of stations; a control station;and connection means including an enabling control line for coupling thecontrol station to a first remote station which in turn is connected tothe next remote station in cascade and so on until the final remotestation; the control station including means for enabling the firstremote station in the cascade by applying an enabling pulse thereto viasaid connection means and each of the remote stations including meansfor relaying the enabling pulse to the next station, so that the remotestations are sequentially enabled, said control station furtherincluding means for causing the cycle enabling said remote stations insequence to be constantly repeated while the machine is in operation;said connection means further including means having a clock lineconnected to each station for applying a sequence of timing pulses tothe stations and means having an information line to which each stationis connected in parallel for transferring fault and/or control signalsbetween the remote stations and the control station.
 27. A machine forhandling or processing material, consisting of a plurality of remotestations coupled in cascade with a control station; said control stationincluding means for applying an enabling pulse to the first remotestation in the cascade, and each remote station including means forrelaying said enabling pulse to the next remote station in the cascadeso that each remote station receives said enabling pulse during arespective time slot of a time frame; at least one of said remotestations being an input station arranged when enabled to receive aninformation signal representing the condition of an associated detectorincluding means for relaying said information signal to the controlstation; and at least one of said remote stations being an outputstation arranged when enabled to supply a machine control signal to anassociated machine part effecting a change in the operating procedure.28. A machine according to claim 27, including means having a clock linefor applying a series of clock pulses from the control station to all ofthe remote stations.
 29. A machine according to claim 28, includingmeans having an information line for relaying said information signalsfrom said remote stations to said control station and for supplying saidcontrol signals from said control station to said remote stations.
 30. Apackaging machine, for packaging cigarettes or other rod-like articlesof the cigarette industry, comprising a plurality of separate machineparts for effecting respective operations associated with suchpackaging, a plurality of remote stations respectively connected to someor all of said parts, each remote station comprising an input stationarranged, when interrogated, to receive signals from the respective partsignifying the presence of a fault or other special condition, orcomprising an output station arranged, when interrogated, to supply amachine control signal to the associated part, a control center stationconnected with all the remote stations in cascade and including meansfor interrogating the first remote station in the cascade, each stationincluding means for relaying an interrogation signal to the next stationso that the remote stations are sequentially interrogated in turn, thesystem including also an information line for transferring fault andcontrol signals between the remote stations and the control centerstation, each remote station comprising an indicating device forindicating when a remote station is being interrogated, and wherein theindicating devices are light emitting diodes.
 31. A packaging machine,for packaging cigarettes or other rod-like articles of the cigaretteindustry, comprising a plurality of separate machine parts for effectingrespective operations associated with such packaging, a plurality ofremote stations respectively connected to some or all of said parts,each remote station comprising an input station arranged, wheninterrogated, to receive signals from the respective part signifying thepresence of a fault or other special condition, or comprising an outputstation arranged, when interrogated, to supply a machine control signalto the associated part, a control center station connected with all theremote stations in cascade and including means for interrogating thefirst remote station in the cascade, each station including means forrelaying an interrogation signal to the next station so that the remotestations are sequentially interrogated in turn, the system includingalso an information line for transferring fault and control signalsbetween the remote stations and the control center station, each remotestation comprising an indicating device for indicating when a remotestation is being interrogated, and wherein the control station comprisesmeans for manually generating a check interrogation control signal whichwill interrogate all the remote stations between the check signal outputand a fault in the interrogation line, to activate the indicatingdevices on those remote stations, thereby to indicate the position ofthe line fault.